__gcd without func

#include<bits/stdc++.h>
using namespace std;
int main(){
	int t,n,x;
	cin>>t;
	while(t--){
		cin>>n;
		int a[1010]={0};
		for(int i=1;i<=n;i++){
			cin>>x;
			a[x]=i;
		}int cnt=-1;
		for(int i=1;i<=1000;i++) {
			for(int j=i;j<=1000;j++){
				if(a[i]!=0&&a[j]!=0&&a[i]+a[j]>cnt&&__gcd(i,j)==1)cnt=a[i]+a[j];
			}//             u need to #include<algorithm>~~~~~~~~~
		}printf("%d\n",cnt);
	}
}